Awareness is a useful break reminder, helps you become aware of time spent on the computer. It accomplishes this by playing the sound of a Tibetan singing bowl to mark every hour of continuous computer use. It also displays how long youve been using your computer without a break in the menu bar.
Awareness will help you keep track of the time you spend in front of your PC and is designed to remind you when its time to take a break from your work.
Limitations:
* You will only be asked to pay for it if you continue to use it for a few days.

The license of this software is Free Trial Software, the price is $1.99, you can free download and get a free trial.